- Overview
  - Polymyxin B sulfate is a polypeptide antibiotic and is composed of polymyxins B1, B2, and B3 with fractions B1 and B2 comprising the majority of the mixture. Polymyxin B6 sulfate is freely soluble in aqueous solution (25 mg/mL). Polymyxin B components are structurally identical with the exception of a variable fatty acid group on each fraction. Results from in vitrostudies have shown marginal differences in MIC data when comparing the fractions.
    
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    Background
    
    Polymyxin B targets and alters permeability lipopolysaccharide (LPS) of Gram-negative bacteria leading to lysing of the cell. Polymyxin B only needs to interact with LPS, it is not required to enter the cell.
- Properties
  - Molecular Formula
    
    C56H98N16O14 • xH2SO4 (lot specific)
    
    Molecular Weight
    
    1219.47 (Free base)
    
    Other Properties
    
    Source: Bacillus polymyxa
    Purity Level: >90.0%
    
    Storage
    
    -20°C
    
    * For research use only
- Applications
  - Application Description
    
    Spectrum: Polymyxin B Sulfate targets the outer membrane of Gram-negative bacteria especially Pseudomonas aeruginosa.
    
    Microbiology Applications: Polymyxin B Sulfate is commonly used in clinical in vitro microbiological antimicrobial susceptibility tests (panels, discs, and MIC strips) against Gram-negative microbial isolates. Medical microbiologists use AST results to recommend antibiotic treatment options. Representative MIC values include:
    Pseudomonas aeruginosa 0.25 µg/mL – 1 µg/mL
    Media Supplements
    Polymyxin B is routinely used as a selection agent in several types of isolation media:
    Perfringens agar - Supplement A and Supplement B
    Perfringens Agar - SFP and TSC Selective Supplements
    Columbia Blood Agar - Campylobacter Selective Supplement (Skirrow)
    Columbia Blood Agar - Campylobacter Selective Supplement (Blaser-Wang)
    Brucella medium - Brucella Selective Supplement
    MYP Agar - Polymyxin B Bacillus Selection Supplement
    Legionella CYE Agar - Legionella BMPA-α Selective Supplement
    Legionella CYE Agar - Legionella MWY Selective Supplement
    Campylobacter Agar - Campylobacter Selective Supplement (Preston)
    PALCAM Agar - PALCAM Selective Supplement
    Legionella CYE Agar - Legionella GVPC Selective Supplement
    m-CP Medium - Membrane C. perfringens Selective Supplement
    Burkholderia cepacia Agar Base - Burkholderia cepacia Selective Supplement
    ORSAB - ORSAB Selective Supplement
    Campylobacter Agar Base - Modified Preston Campylobacter Selective Supplement
    Brucella Medium Base - Modified Brucella Selective Supplement
    Legionella CYE Agar - Legionella GVPN Selective Supplement
    Chromogenic Listeria Agar - Chromogenic Listeria Selective Supplement
    Chromogenic Bacillus cereus Agar - Chromogenic Bacillus cereus Selective Supplement
    Chromogenic Listeria Agar - Chromogenic Listeria Differential Supplement
    
    Plant Biology Applications: Polymyxin B Sulfate was successfully tested to counteract phytopathogenic Gram-negative bacterial growth including different strains of Pseudomonas viridiflava and Erwinia carotovora. Polymixin B Sulfate was shown to reduce bacterial growth of different strains of Pseudomonas viridiflava at low concentrations, (0.08 µg/ml) and Erwinia carotovora growth at slightly higher concentrations (0.25 µg/ml) (Selim et al, 2005). Polymyxin B has been shown to elict alkaloid accumulation in E. californica. Treatment at 0.04 mg/ml for 4 hours showed a 5.5 times increase in Jasmonate levels over the control (water).